Customers enter a McDonald's restaurant in Los Angeles on Monday, July 28, 2008.

The Dollar Menu has failed to lift sales for fast food burger chain McDonald's. The company announced on Friday that an important sales measurement had fell 1 percent over the period, and that it expects it to fall again in April.

The announcement meant it was the first quarterly decline in 10 years at restaurants open at least 13 months, according to the Associated Press.

McDonald's has pushed the publicity of its Dollar Menu and other special deals over the past year as competition with Burger King and Wendy's and others steps up. The strategy has worried some though, who believe it is eating into the company's profit margins.

However, despite the concerns, McDonald's executives held a conference call on Friday where they insisted the cheaper prices were necessary and important in the present economic climate.

"That battle for market share has become so critical for the long-term health of business, we're willing to sacrifice that margin," said Peter Bensen, the company's chief financial officer, according to AP.

However, the pushing of the discount menus has disgruntled some of those independent franchises who operate restaurants. Some have complained about the large use of discount coupons as well as the discounts they are being forced to offer as part of the franchise.

Looking at the wider fast food industry, some competitors are also following suit; Burger King has shaken up its own strategy and is now offering a discount deal for a $1.29 Junior Whopper. Wendy's also has offered numerous discount deals over the past year to offer its customers more options and to stay competitive.